The long-term objective of proposed research is to identify and characterize those steps in viral RNA metabolism at which virus expression in cytomegalovirus (CMV) infected cells is regulated. The research plan is designed to investigate regulation at primary transcription and during post-transcriptional processing. Primary transcription is to be examined by liquid DNA/RNA hybridization to determine the extent of transcription occurring at different times postinfection and to estimate the number of classes and relative amounts of viral transcripts. Initially, the complete CMV genome will be used to detect and quantitate viral transcripts. Subsequently restriction endonuclease fragments will be employed. In this way a transcription map of the CMV genome can be constructed. To detect post-transcriptional regulation viral RNA sequences found in polyribosomes will be compared to those present in the nucleus. Polyadenylation and preferential translation of viral RNA transcripts will be investigated.